Breath Is Life
What does it mean to be alive, to inhabit and animate a body? What is our purpose on this planet that revolves around a star that we call the sun? These questions have been the subject of extensive musings and debate since the dawn of humanity, resulting in a wide range of diverse and even conflicting opinions. However, we can all agree on this point: our bodies require certain external inputs to sustain life, such as food and water and yes, air. You may have heard it said that the average human can exist three weeks without food, three days without water, but only three minutes without air. Ironically, we pay much more attention to the consumption of food and water than we do to our breathing. We tend to take our breathing for granted. It just happens.
Let’s have a closer look at breathing. On average, an adult individual will inhale and exhale at a rate of 12 to 18 breaths per minute, or roughly 17,000 to 26,000 breaths per day. The volume of each breath (tidal volume) is about 0.5 liters (0.13 gallons) of air. So our lungs are processing 8,500 to 13,000 liters of air per day. That is a lot! If we zoom in a bit further, we will find that at sea level and for a temperature of 25 C (77 F), that corresponds to 2.1 x 1026 to 3.2 x 1026 molecules of air! Note that 1026 represents the number one with 26 zeros behind it. Not all of this air makes its way into our blood. This is good because that volume of air would weigh 100 kg (45 lbs) to 150 kg (69 lbs). Our bodies are capable of extracting the needed oxygen molecules from the air, filtering out the bacteria, dust, and pathogens, which should not be entering our bodies, and expelling the carbon dioxide produced through the process of converting glucose to energy for metabolically active tissues. Not a bad day’s work for a process that just happens.
Breathing as a Gateway to the Autonomic Nervous System
It is true that our breathing primarily occurs as an involuntary response to signals sent to our chest and diaphragm from the medulla oblongata located at our brain stem; however, we can consciously override these signals (at least temporarily) to take control of our respiration rate and pattern. This is actually a rather amazing and empowering feature of our bodies. Why? Because our breathing directly affects other facets of the autonomic nervous system, such as heart rate, how blood is directed to various parts of our bodies, digestion, level of alertness, and much, much more. That is, by consciously controlling our breathing, we can exercise a certain level of autonomy on our autonomic nervous system.
The autonomic nervous system is part of the peripheral nervous system that regulates involuntary physiological processes. The autonomic nervous system consists of three major divisions:
- Sympathetic nervous system
- Parasympathetic nervous system
- Enteric nervous system
We can focus on the first two of these. The sympathetic nervous provides the body with a means of preparing for situations that are stressful and require heightened levels of activity in the body. It is associated with the “fight or flight” response. In contrast, the parasympathetic nervous system is responsible for the day-to-day, business-as-usual functions of the body. It is often referred to as the “rest and digest” or “feed and breed” system. Having a healthy, functioning sympathetic nervous system is vital for survival and some degree of stimulation at this level can be good for us. However, we were not designed to remain in the fight or flight mode for extended periods of time. The pressures of our current society often drive people to either remain in fight or flight or rapidly switch between sympathetic and parasympathetic response modes. When we find ourselves stressed, anxious, angry, or such (aspects of the fight or flight mode), it can be helpful to use the breath to activate the parasympathetic nervous system and restore balance in our lives.
So, our breathing affects our bodies. But the cycle continues because activity in the body affects the brain via communications to the brain conducted through various nerve channels, one of which being the vagus nerve. Approximately 80% of the signal traffic on the vagus nerve is carried from the body to the brain (efferent) with the remaining 20% being transmitted from the brain to the body (afferent). In summary, our breathing affects the functions of our body and the activity in our body affects our brains. As such, our breath impacts how we think! This is an oversimplification, but hopefully, it gets the fundamental ideal across.
As leaves move in the wind, your mind moves with your breath.
B. K. S. Iyengar
Deep Breathing
What does it mean to take a deep breath? For many, this implies taking a full breath, often involving lifting of the shoulders and the activation of the muscles in the chest (thoracic breathing). However, the process of taking a deep breath actually means the circulation of air deep into our lungs. This is most effectively achieved by taking long slow breaths driven through the movement of the diaphragm. Through the process of diaphragmatic breathing, there is a better chance of bringing fresh air into the alveolar spaces located in the lower portions of our lungs. Because of gravity and possibly dysfunctional breathing patterns, the flow of blood to the lungs tends to favor the lower lobes (bottom of the lungs). So, it is advantageous to take deep breaths to facilitate better gas exchange between the lungs and the blood. It is interesting to note that the introduction of nitric oxide into the lungs, as produced in the paranasal cavities, has the effect of redistributing the blood more evenly through the lungs. This can be attributed to the effect of nitric oxide on opening up the blood vessels.
When we mouth-breathe, shallow-breathe, chest-breathe, and rapid-breathe, the air circulated in the lungs will predominantly reach the upper portions of the lungs. Moreover, by mouth breathing, the availability of nitric oxide in the lungs is dramatically decreased, causing the flow of blood to be channeled to the lower lobes of the lungs.
Nasal Breathing
Over time, our bodies have learned to efficiently and effectively deal with changes in our internal and external environments. We have numerous feedback loops built into our physiology specifically designed to maintain homeostasis in our bodies. For example, our feedback loops strive to maintain an appropriate balance of our internal temperature, heartbeat rate, blood pressure, blood pH, respiration rate, and so forth. There is literally wisdom in our cells. However, we are pushing this wisdom to new limits. We are in a period of human development when our technological and societal advancements (and sometimes regressions) have outpaced our physiological ability to adapt. This has become evident, for example, in our breathing.
We have naturally evolved to be nasal breathers. The remarkable physiological design of the airways and the chemical reactions associated with the exchange of oxygen and carbon dioxide between the lungs and blood vessels are optimized for breathing through the nose. The nasal passage heats, moistens, and filters air before it enters the lungs. It also offers a calibrated level of resistance to prevent us from over-breathing. As air is passed back out through the nasal passage, the heat and moisture are partly recovered before the exhalation. None of these benefits are available during mouth breathing. In fact, mouth breathing was considered a sign of ill health. This is true for animals as well.
The nose is for breathing, the mouth is for eating.
Proverb
Despite the natural advantages of nasal breathing, our lifestyles are creating conditions that are driving people to breathe more and more through the mouth. There are numerous factors contributing to this transition. Changes in our diet are causing physiological changes to our faces and airway passages. Our chins and jaws are becoming more set back, the arch at the roofs of our mouths are becoming higher, our teeth are coming in more crooked, and our airways are becoming more constricted. All of these changes are pushing people to become mouth breathers. Making matters worth, the process of mouth breathing exacerbates the problem by further promoting these maladaptations. The fast-paced and stressful environments that many of us find ourselves confronting tend to lead to chest breathing as well. In turn, chest breathing can make one more prone to mouth breathing. This is explored in more detail in other sections of this website.
Basically, the best advice for normal breathing is this: “Shut your mouth!”
Slow Breathing
Our society tends to be driven by the mantra that more is better. We have become fascinated with larger houses, more powerful corporations, faster delivery of goods to our homes, super-sized meals and beverages, more product selection, and so forth. Perhaps not surprisingly, we have also become a society of over-breathers. Many people have respiration rates that exceed their needs. As we rely more on mouth breathing and chest breathing, our respiration becomes inefficient and we are not able to effectively exchange gases in our lungs with our blood. Consequently, we may develop a hunger for more air, which causes us to increase our rate of breathing.
When it comes to our breathing, we would be well served by adopting the mindset that less is more. By breathing slowly and deeply through the nose with the assistance of the diaphragm, we can better oxygenate our blood and cells. In the process, we are conserving energy by not over-exerting our respiratory system. Note that slow breathing should be accompanied by deep diaphragmatic breathing through the nose. Efficient breathing is an integral process.
The Role of Carbon Dioxide in Breathing
Most people will know that carbon dioxide is produced in the body during the process of aerobic and anaerobic respiration. It is also known that carbon dioxide is expelled during exhalation as waste gas. As such, there is a belief that we should attempt to expel as much carbon dioxide as possible. But this is only part of the story and there is more to be known about carbon dioxide. Carbon dioxide actually plays an important role in the release of oxygen throughout the body from the oxygenated hemoglobin molecules found in the red blood cells. The actual process by which carbon dioxide facilitates the release of oxygen from hemoglobin (known as the Bohr Effect) is not important for this discussion. But it is interesting to note that it has been known since the beginning of the 20th century. However, this particular function of carbon dioxide in the respiration process is often overlooked.
Anyone who has held his or her breath long enough will have experienced a sensation known as air hunger. As the presence of carbon dioxide builds in the blood and levels of oxygen decrease, receptors in the body send signals to trigger breathing. This feeling can become quite uncomfortable and at some point, the diaphragm and other muscles associated with breathing will begin to involuntarily spasm. You are forced to either draw in air or pass out from the lack of oxygen. If you were to measure the oxygen and carbon dioxide levels in the blood before the sensation of discomfort or muscle spasms begins, you would notice that the blood contains plenty of oxygen but there would be a moderately elevated level of carbon dioxide. The additional carbon dioxide would actually assist in the delivery of oxygen. There are exercises that one can perform to increase the body’s tolerance to the build-up of carbon dioxide.